Frequently Asked Questions
I've got a small ceramic disk capacitor, how can I tell it's value?  

The first row will have a number like 33J, 104Z or 223Z, where first two digits denote significant figures; the last digit denotes the multiplier of 10 in pF. The letter denotes the tolerance, for which you should check the product data sheet. If there is a second row this will be the Manufacturer's Identification.
Examples:
33J = 33 x 10^{0} pF = 33pF 104Z = 10 x 10^{4} pF = 0.1μF 223Z = 22 x 10^{3} pF = 22nF  
What are the colour bands on a resistor?  
Many resistors have 4 bands:
It's also common to find 5 Band resistors that will have 3 digits before the multiplier and tolerance, whereas a 6^{th} Band show a temperature coefficient. eg. Brown Green Red Gold = 15 x 10^{2} = 1500Ω also written 1K5 When we write 1K5 the K in the middle means thousand and replaces a decimal point that might be missed. Similarly we can use R and M for other factors, where 2R2 would be 2.2Ω and 5M6 would be 5.6MΩ or 5.6 x 10^{6}.  
Colour 
Black

Brown

Red

Orange

Yellow

Green

Blue

Violet

Grey

White

Number 
0

1

2

3

4

5

6

7

8

9

How do compare different torque units?  
There are a variety of units used, most common is Nm (Newton meters) but with small values you might see Nmm (Newton millimetres). This is relatively straight forward as there is a factor of 1000 between the two (1m = 1000mm), unfortunately other measures are also common but all are based on distance x force so conversions are not difficult. 
in.oz

lb.ft

kg.cm

g.cm

N.m
 
in.oz

1

0.00521

0.072

72

0.00706
 
lb.ft

192

1

13.8

13800

1.36
 
kg.cm

13.9

0.0723

1

1000

0.0981
 
g.cm

0.0139

0.0000723

0.001

1

0.0000981
 
Nm

142

0.738

10.2

10200

1
 
In the case of in.oz (inch ounce) or kg.cm (kilogram centimetre) they are often depicted at in.ozf or kgf.cm to show a measure of force rather than mass.  
What about other Frequently Asked Questions?  
John Piccirillo's Robotics miniFAQ for Beginners can be found here as a PDF, updated Aug 2006.
The Robot Competition FAQ can be found here, and contains contains brief summaries of regular robot competitions around the world. 
ReferenceMaterial